- How dust and fumes can be hazardous to health -

Processes that create hazardous dust and fume

Many industrial processes can generate harmful dust and fume. Essentially any operation where a material is cut, marked or physically altered in any way has the potential to produce harmful materials.

Some common processes which produce harmful fumes:

• Machine Soldering
• Laser engraving and marking
• Welding
• Hand Soldering
• Printing
• Pharmaceutical manufacture

Soldering - An example of a hazardous process.

HSE statistics (2004/05) showing incidence rates of occupational asthma reported by chest physicians puts rosin based solder flux fume in the top ten.

Occupational asthma is an allergic reaction that can occur in some people when they are exposed to certain substances in the workplace, for example solder fume. These substances are called 'respiratory sensitisers' or asthmagens. They can cause a change in people’s airways, known as the 'hypersensitive state'. Not everyone who becomes sensitised goes on to get asthma. But once the lungs become hypersensitive, further exposure to the substance, even at quite low levels, may trigger an attack.

Early symptoms from fume exposure can include:

• watering, prickly eyes
• running or blocked nose
• sore throat
• coughing, wheezing, tight chest and breathlessness.

Rosin based solder flux fume is generated when rosin based solder flux is heated. During hand soldering the fume rises vertically on thermal currents created by the heat of the iron, entering the breathing zone of the worker as they lean over their work. The quantity of fume emitted will depend on a number of variables including: the rosin content; the solder temperature; and the size, spread and number of joints being worked.

Assuming substitution is not possible and the lowest rosin content solder flux for the job has been selected the main emphasis is to optimise the solder temperature and to provide effective fume extraction. Solder machines should always be enclosed and extracted. Whilst for hand soldering the extraction control solutions will depend on:

• the soldering temperature,
• the soldering time,
• the size, spread and number of joints being worked,
• the shape of the workpiece,
• the size of the work area; and
• the number of people soldering per period.

Rosin based solder flux fume (RBSFF) is a hazardous substance under COSHH 2002 (as amended) and has been assigned both a “sen” notation and a “skin” notation indicating it is capable of causing both occupational asthma and skin sensitisation. RBSFF has Work Place Exposure Limits (WELs) of:

• 0.05 mg/m3 – 8 Hr time weighed average (full shift exposure averaged over eight hours); and
• 0.15 mg/m3 – 15 minute TWA (15-minute reference period)

Example Case

Solderer develops asthma at large manufacturers in Gloucester - from the UK HSE

An employee developed occupational asthma after working for a large multi-national company in Gloucester. He was employed between 1995 and 2004 as a solderer and was exposed to rosin based (colophony) solder fume during his career.

His health was deteriorating from 1999 onwards, and was taking time off work due to breathing difficulties. The company did not have adequate control measures in place and failed to install fume extraction equipment to remove rosin based fumes from the workroom air or from the breathing zones of its solderers.

The company did not substitute the rosin based solder with rosin free solder until December 2003, despite an assessment having identified the need to in 1999. Employees, including the asthma suffer were not placed under a health surveillance scheme at any time.

As a result of action taken by HSE the company was fined £100,000 with £30,000 costs. This attracted local and national media attention.

Laser Marking - An example of a hazardous process.

CO2, YAG and Diode lasers are commonly used to code, mark, engrave, weld or cut components or products which are manufactured from a variety of materials. Hazardous fumes and dust are produced when the substrate, lacquer, paint or coating is marked or cut. Purex systems not only ensure compliance with International Health and Safety Law but also deliver actual cost savings to the production process.